Integrated system for methane cracking, calcium carbide synthesis and methanol production by heat storage of molten medium

Abstract

This invention discloses an integrated system for molten medium thermal storage methane cracking, calcium carbide synthesis, and methanol production, comprising a methane feed gas unit, a methane cracking unit, a separation unit I, a calcium carbide synthesis unit, a gas purification unit, a methanol synthesis tower, and an energy recovery and power generation unit. The calcium carbide synthesis unit includes a calcium carbide synthesis reactor, a carbon black storage tank, a calcium oxide preheating furnace, a mixing and molding unit, and a separation unit II. The methane cracking unit includes a methane cracking reactor and a heat exchanger I. A molten metal circulation pipeline is provided between the methane cracking reactor and the calcium carbide synthesis reactor. This invention can reduce the heating energy consumption of the calcium carbide synthesis and methane cracking processes, improve the temperature distribution uniformity within the reactor, and integrate the calcium carbide production, methane cracking, and methanol synthesis processes, achieving energy and material coupling across multiple units. This increases the reaction rate and significantly reduces synthesis energy consumption and total system energy consumption, significantly improving energy utilization efficiency during operation.

Description

Technical Field

[0001] This invention relates to the field of energy and chemical technology, specifically to an integrated system for molten medium thermal storage of methane cracking, calcium carbide synthesis, and methanol preparation. Background Technology

[0002] The energy and chemical industry is facing continuous pressure to transform towards green, low-carbon, and efficient production models. In this process, calcium carbide (CaC2) and methanol (CH3OH), as two key basic chemical raw materials, typically face a series of technical challenges that urgently need to be optimized in terms of energy efficiency and carbon emissions in their mainstream production processes.

[0003] The traditional calcium carbide synthesis process is extremely energy-intensive. Its core reaction is CaO + 3C → CaC2 + CO, which is a strongly endothermic reaction. In existing technologies, this reaction needs to be carried out in an electric arc furnace at extreme temperatures of 2000~2200℃, resulting in huge energy consumption and production costs. This process is highly dependent on raw materials and puts pressure on the environment. Its carbon source is heavily dependent on high-quality petroleum coke or anthracite. These raw materials have limited reactivity and fluctuate greatly in price. In addition, the process produces a large amount of CO as a byproduct, which is often used as low-value fuel gas or directly burned and emitted in the existing technology system, resulting in the waste of carbon resources and additional environmental burden.

[0004] In the field of methanol synthesis, the technological bottleneck mainly lies in the preparation of upstream feedstock gas. Currently, industrial methanol synthesis heavily relies on syngas (H2 / CO) obtained from coal, natural gas, or heavy oil processing. Whether it is coal gasification or natural gas reforming, the gas production process itself is accompanied by significant energy consumption and carbon dioxide emissions, which restricts the carbon emission reduction potential of the methanol industry throughout its entire life cycle.

[0005] Furthermore, in the field of energy and chemical engineering, methane thermal cracking for hydrogen production (CH4→C+2H2) has received widespread attention in recent years as a potential pathway for low-carbon hydrogen energy production. However, this technology also faces significant challenges. The reaction needs to be carried out at temperatures above 1200℃, resulting in high energy consumption. Moreover, the solid carbon byproducts are typically low-value-added carbon black, which has weak market competitiveness. It usually requires complex and costly post-processing to achieve effective value-added, which severely restricts the overall economic viability and commercial prospects of this pathway. Therefore, a molten medium thermal storage integrated system for methane cracking, calcium carbide synthesis, and methanol preparation has been developed to address the shortcomings of the existing processes in terms of energy efficiency, resource utilization, and system integration. Summary of the Invention

[0006] To address the problems mentioned in the background section, this invention provides an integrated system for molten medium thermal storage methane cracking, calcium carbide synthesis, and methanol production. This system reduces heating energy consumption in calcium carbide synthesis and methane cracking processes, improves temperature distribution uniformity within the reactor, and integrates calcium carbide production, methane cracking, and methanol synthesis processes. This integration achieves energy and material coupling across multiple units, thereby increasing the reaction rate, reducing synthesis energy consumption and total system energy consumption, significantly improving energy utilization efficiency during operation, and realizing efficient energy integration and cascade utilization. Furthermore, by converting carbon-containing byproducts into resources, carbon emissions are reduced at the source.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an integrated system for molten medium thermal storage of methane cracking, calcium carbide synthesis and methanol preparation, comprising a methane feed gas unit, a methane cracking unit, a separation device I, a calcium carbide synthesis unit, a gas purification unit, a methanol synthesis tower and an energy recovery and power generation unit; The methane cracking unit includes a methane cracking reactor and a heat exchanger I. The methane feed gas unit input is transported to the methane cracking reactor after passing through the heat exchanger I. The calcium carbide synthesis unit includes a calcium carbide synthesis reactor, a carbon black storage tank, a calcium oxide preheating furnace, a mixing and forming unit, and a separation device II. A molten metal circulation pipeline is provided between the methane cracking reactor and the calcium carbide synthesis reactor, and a high-temperature pump is provided on the molten metal circulation pipeline. The output of the methane cracking reactor is connected to separation device I. The output of separation device I is connected to heat exchanger II. Cooling water pipeline I is installed at the input of heat exchanger II. The output of heat exchanger II is connected to heat exchanger I. The output of heat exchanger I is connected to heat exchanger III. Cooling water pipeline II is installed at the input of heat exchanger III. The solid nano-carbon black produced by the methane cracking reactor after passing through separation device I is transported to a carbon black storage tank. The carbon black storage tank and the calcium oxide preheating furnace are respectively connected to a mixing and forming unit. The calcium oxide preheating furnace is equipped with a calcium oxide feed pipeline. The mixing and forming unit thoroughly mixes the preheated calcium oxide and the nano-carbon black output from the carbon black storage tank. The mixed material output from the mixing and forming unit enters the calcium carbide synthesis reactor. The calcium carbide synthesis reactor outputs high-temperature crude calcium carbide synthesis by-product gas to the calcium oxide preheating furnace for heating. The output of the calcium carbide synthesis reactor is connected to a heat exchanger. IV. The heat exchanger IV is equipped with a cooling water pipeline III at its input and a CaC2 pipeline at its output. The crude calcium carbide synthesis byproduct gas output from the calcium oxide preheating furnace, after heat exchange with calcium oxide, is sent to the separation device II. The output of the separation device II is connected to a heat exchanger V, and the output of the heat exchanger V is connected to a heat exchanger VI. The input of the heat exchanger V is equipped with a cooling water pipeline IV, and the heat exchanger VI is connected to the output of the gas purification unit. The high-temperature crude calcium carbide synthesis byproduct gas, after heat exchange with calcium oxide, exchanges heat with the cooling water in the cooling water pipeline IV. The energy recovery power generation unit includes a generator, and heat exchangers II, III, IV and V are respectively connected to the generator for output. The output of heat exchanger III is connected to heat exchanger VII. The gas purification unit includes a gas separation device. The H2 produced by the gas separation device is sent to the methanol synthesis tower after passing through heat exchanger VII. The output of the methanol synthesis tower is connected to a crude methanol storage tank. The output of the gas separation device is connected to a CO storage tank. The high-temperature crude calcium carbide synthesis by-product gas is heat exchanged with the cooling water in cooling water pipeline IV in heat exchanger V after passing through calcium oxide heat exchanger. Then, it is heat exchanged with the CO output from the CO storage tank through heat exchanger VI. The output of heat exchanger VI is connected to the methanol synthesis tower. The CH4 output from the gas separation device is returned to the methane feed gas unit.

[0008] As a preferred embodiment of the present invention, the separation device I and the separation device II are cyclone separators.

[0009] As a preferred embodiment of the present invention, the methanol synthesis tower is provided with a heat exchange unit, and a steam drum is provided at the top of the methanol synthesis tower.

[0010] As a preferred embodiment of the present invention, the methane cracking reactor is a vertical pressure vessel, the methane cracking reactor is provided with a molten metal coil, the calcium carbide synthesis reactor is surrounded by an induction coil, and the calcium carbide synthesis reactor is internally provided with a heating section connected to the molten metal circulation pipeline.

[0011] As a preferred embodiment of the present invention, the molten metal circulation pipeline carries high-temperature molten metal, which serves as a heat transfer medium and is made of a high-temperature nickel-based alloy.

[0012] As a preferred embodiment of the present invention, the carbon black storage tank is lined with refractory material, the interior of the carbon black storage tank is provided with a high-temperature sealed heat-insulating silo, the carbon black storage tank is provided with a nitrogen or argon gas protection interface, and the outlet end of the carbon black storage tank is provided with a metering feeder.

[0013] As a preferred embodiment of the present invention, the mixing and molding unit uses a high-temperature twin-shaft paddle mixer for mixing.

[0014] As a preferred embodiment of the present invention, the particle size of the calcium oxide feed pipeline is 50~500μm, and the temperature of the by-product gas of the calcium carbide synthesis reactor is 1800~1900℃. This gas is used as a heat source to enter the calcium oxide preheating furnace for heat exchange, preheating the raw material of the calcium oxide feed pipeline to 900℃.

[0015] As a preferred embodiment of the present invention, the generator is a steam turbine generator set, which includes a steam turbine and a condensing system.

[0016] By adopting the above technical solution, the advantages of the present invention compared with the prior art are: 1. A molten metal circulation pipeline is installed between the methane cracking reactor and the calcium carbide synthesis reactor. By constructing a molten metal circulation system, the calcium carbide synthesis reactor heats the metal medium to maintain it at 1900~2000℃, and drives it through a high-temperature pump to circulate the molten metal medium to the methane cracking unit, providing a stable reaction temperature of 1700~1850℃. Compared with traditional resistance or electric arc heating methods, this system improves the uniformity of temperature distribution within the reactor and reduces heat loss, thereby reducing energy consumption per unit product and improving the stability of reaction operation.

[0017] 2. A cross-system material recycling network of methane-calcium carbide-methanol was constructed. The nano-carbon black by-product of the methane cracking unit was used as a high-quality carbon source for calcium carbide synthesis. The CO by-product of calcium carbide synthesis and the high-purity H2 generated from methane cracking were mixed in a certain ratio to prepare methanol. This system enables all by-products to be utilized in a high-value manner, realizing the directional conversion of carbon elements and carbon emission reduction.

[0018] 3. By utilizing the properties of nano-carbon black, the uniform mixing of calcium oxide and carbon source is achieved, reducing the reaction energy consumption of the calcium carbide synthesis unit and realizing a multi-product co-production mode of calcium carbide, hydrogen and methanol.

[0019] 4. By constructing an efficient energy cascade utilization system, the system achieves synergistic integration of energy among different process units. The system makes full use of the heat generated in the reaction process and recovers and utilizes the reaction heat in a cascade manner through waste heat power generation, raw material preheating and medium heating, thereby reducing the total energy consumption of the system and improving energy utilization efficiency. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the system configuration of the present invention; In the diagram: 1. Methane feed gas unit; 2. Separation unit I; 3. Methanol synthesis tower; 4. Methane cracking reactor; 5. Heat exchanger I; 6. Calcium carbide synthesis reactor; 7. Carbon black storage tank; 8. Calcium oxide preheating furnace; 9. Mixing and forming unit; 10. Separation unit II; 11. Molten metal circulation pipeline; 12. High-temperature pump; 13. Heat exchanger II; 14. Cooling water pipeline I; 15. Heat exchanger III; 16. Cooling water pipeline II; 17. Calcium oxide feed pipeline; 18. Heat exchanger IV; 19. Cooling water pipeline III; 20. CaC2 pipeline; 21. Heat exchanger V; 22. Heat exchanger VI; 23. Cooling water pipeline IV; 24. Generator; 25. Heat exchanger VII; 26. Gas separation equipment; 27. Crude methanol storage tank; 28. CO storage tank; 29. ​​Molten metal coil; 30. Induction coil; 31. Heating section. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0022] Please see Figure 1 The present invention provides a technical solution: an integrated system for molten medium thermal storage of methane cracking, calcium carbide synthesis and methanol preparation, including a methane feed gas unit 1, a methane cracking unit, a separation device 12, a calcium carbide synthesis unit, a gas purification unit, a methanol synthesis tower 3 and an energy recovery and power generation unit; The methane cracking unit includes a methane cracking reactor 4 and a heat exchanger I5. The methane feed gas unit 1 is fed into the methane cracking reactor 4 after passing through the heat exchanger I5. The calcium carbide synthesis unit includes a calcium carbide synthesis reactor 6, a carbon black storage tank 7, a calcium oxide preheating furnace 8, a mixing and forming unit 9, and a separation device II10. A molten metal circulation pipeline 11 is provided between the methane cracking reactor 4 and the calcium carbide synthesis reactor 6. A high-temperature pump 12 is installed on the molten metal circulation pipeline 11. The output of the methane cracking reactor 4 is connected to the separation device I2. The output of the separation device I2 is connected to the heat exchanger II13. The input of the heat exchanger II13 is connected to the cooling water pipeline I14. The output of the heat exchanger II13 is connected to the heat exchanger I5. The output of the heat exchanger I5 is connected to the heat exchanger III15. The input of the heat exchanger III15 is connected to the cooling water pipeline II16. After passing through separation device I2, solid nano-carbon black is produced in methane cracking reactor 4 and transported to carbon black storage tank 7. Carbon black storage tank 7 and calcium oxide preheating furnace 8 are respectively connected to mixing and forming unit 9. Calcium oxide preheating furnace 8 is equipped with calcium oxide feed pipeline 17. Mixing and forming unit 9 thoroughly mixes the preheated calcium oxide and the nano-carbon black output from carbon black storage tank 7. The mixed material output from mixing and forming unit 9 enters calcium carbide synthesis reactor 6. Calcium carbide synthesis reactor 6 outputs high-temperature crude calcium carbide synthesis by-product gas to calcium oxide preheating furnace 8 for heating. Heat exchanger IV18 is connected to the output of calcium carbide synthesis reactor 6. The input of heat exchanger IV18 is equipped with cooling water pipe III19, and the output of heat exchanger IV18 is equipped with CaC2 pipe 20. The crude calcium carbide synthesis by-product gas after heat exchange with calcium oxide is output from calcium oxide preheating furnace 8 and enters the separation device II10. The output of separation device II10 is connected to heat exchanger V21, and the output of heat exchanger V21 is connected to heat exchanger VI22. The input of heat exchanger V21 is equipped with cooling water pipe IV23, and heat exchanger VI22 is connected to the output of gas purification unit. The high-temperature crude calcium carbide synthesis by-product gas is heat exchanged with calcium oxide and then heat exchanged with the cooling water in cooling water pipe IV23. The energy recovery power generation unit includes a generator 24, and heat exchangers II13, III15, IV18 and V21 are respectively connected to the generator 24 for output. Heat exchanger III15 is connected to heat exchanger VII25. The gas purification unit includes gas separation device 26. The H2 produced by gas separation device 26 is sent to methanol synthesis tower 3 after passing through heat exchanger VII25. The output of methanol synthesis tower 3 is connected to crude methanol storage tank 27. The output of gas separation device 26 is connected to CO storage tank 28. The high-temperature crude calcium carbide synthesis by-product gas is heat exchanged with the cooling water of cooling water pipeline IV23 in heat exchanger V21 after passing through calcium oxide. Then it is heat exchanged with the CO output from CO storage tank 28 through heat exchanger VI22. The output of heat exchanger VI22 is connected to methanol synthesis tower 3. The CH4 output from gas separation device 26 is returned to methane feed gas unit 1.

[0023] In this embodiment, a molten metal circulation pipeline 11 is provided between the methane cracking reactor 4 and the calcium carbide synthesis reactor 6. By constructing this molten metal circulation system, the calcium carbide synthesis reactor 6 heats the metal medium to maintain it at 1900~2000℃, and drives it via a high-temperature pump 12 to circulate the molten metal medium to the methane cracking unit, providing a stable reaction temperature of 1700~1850℃. Compared with traditional resistance or arc heating methods, this system improves the uniformity of temperature distribution within the reactor and reduces heat loss, thereby reducing energy consumption per unit product and improving the stability of the reaction operation. A cross-system material circulation network of methane-calcium carbide-methanol is constructed, using nano-carbon black, a byproduct of the methane cracking unit, as a material for calcium carbide synthesis. The system utilizes high-quality carbon sources, mixing CO, a byproduct of calcium carbide synthesis, with high-purity H2 from methane cracking to produce methanol. This system enables the high-value utilization of all byproducts, achieving targeted carbon conversion and carbon emission reduction. The uniform mixing of calcium oxide and carbon sources is achieved using the properties of nano-carbon black, reducing the reaction energy consumption of the calcium carbide synthesis unit and realizing a multi-product co-production mode of calcium carbide, hydrogen, and methanol. By constructing a fully efficient energy cascade utilization system, energy is synergistically integrated and optimized across different process units. This system fully utilizes the heat generated during the reaction process, recovering and utilizing the reaction heat in a cascade manner through waste heat power generation, raw material preheating, and medium heating, thereby reducing the total energy consumption of the system and improving energy utilization efficiency. Specifically, molten CaC2 output from the calcium carbide synthesis reactor 6 is output as solid CaC2 via heat exchanger IV18, allowing solid calcium carbide to be periodically discharged. The high-temperature byproduct gas is sent to the calcium oxide preheating furnace 8, whose main component is CO, and contains trace amounts of nitrogen and hydrogen carried by the raw materials and generated from side reactions.

[0024] The specific system process principle is as follows: First, raw material gas is input through methane feed gas unit 1, passing through heat exchanger I5 to reach methane cracking reactor 4. The calcium carbide synthesis unit achieves circulation through a molten metal circulation pipeline 11. The calcium carbide synthesis reactor 6 uses induction heating to maintain the metal medium at 1900~2000℃, driven by a high-temperature pump 12, allowing the molten metal medium to circulate to the methane cracking unit, providing a stable reaction temperature of 1700~1850℃. Under these conditions, methane undergoes thermal cracking with a conversion rate exceeding 98%, producing high-purity hydrogen and nano-carbon black. The nano-carbon black has a particle size of 30-300 μm. After the reaction, the gaseous and solid products flow out from the outlet of methane cracking reactor 4. After gas-solid separation by separation device I2, the product gas recovers high-grade heat energy through heat exchanger II13. Cooling water input through cooling water pipeline I14 recovers heat from the product gas. The cooling water exchanges heat with the high-temperature product gas to generate steam, which is sent to generator 24 for steam conversion and power generation. A portion of the product gas output from separation device I2, after passing through heat exchanger II13, enters heat exchanger I5. Subsequently, the product gas containing a small amount of unreacted methane exchanges heat with the methane feed gas, preheating the methane feed gas to 500°C, recovering heat energy, and reducing the risk of subsequent reactions. The corresponding energy consumption is as follows: the product gas after heat exchange with the methane feed gas enters heat exchanger III15 for heat recovery; cooling water input through cooling water pipe II16 exchanges heat with the high-temperature product gas to generate steam, which is then sent to generator 24 for steam conversion and power generation; then the separation device I2 produces solid nano-carbon black, which is transported to carbon black storage tank 7; calcium oxide is input into calcium oxide preheating furnace 8 through calcium oxide feed pipe 17; because the solid nano-carbon black from methane cracking has the characteristics of small particle size and high activity, it can be uniformly attached to the surface of calcium oxide, and after molding, it is prepared into mixed pellets with high reactivity; the fully mixed material enters The calcium carbide synthesis unit includes a preheating furnace 8 that outputs crude calcium carbide synthesis byproduct gas after heat exchange with calcium oxide. This gas is then sent to a separation unit II10 to remove entrained dust, and heat is recovered via heat exchanger V21 to generate electricity in the form of steam. The gas purification unit's gas separation device 26 outputs CO to a CO storage tank 28. The CO output from the CO storage tank 28 is then exchanged with the high-temperature crude calcium carbide synthesis byproduct gas (after heat exchange with calcium oxide and cooling water) via heat exchanger VI22. After heat exchange, the CO enters the gas purification unit, where it is purified and enters the CO storage tank 28. Finally, it passes through heat exchanger VI22 to reach the methanol synthesis unit. Tower 3, in which the H2 produced by the gas separation device 26 is sent to the methanol synthesis tower 3 after passing through heat exchanger VII25, thus the purified CO and H2 enter the methanol synthesis unit in a certain proportion to produce crude methanol, which then reaches the crude methanol storage tank 27; the gas separation device 26 is used to remove impurities present in the methane cracking product gas and crude calcium carbide synthesis by-product gas to obtain product-grade H2 and CO with a purity >99.99%; the methanol synthesis unit is formed by heat exchanger VI22, heat exchanger VII25, CO storage tank 28 and methanol synthesis tower 3, which can accurately control the gas ratio, specifically H2:CO=2.1-2.2, the steam enters the methanol synthesis tower, where it is synthesized into methanol under the action of a catalyst, thus completing the closed-loop conversion from by-product to high-value chemical. The steam is then output through heat exchangers II13, III15, IV18, and V21, which are connected to generator 24. This allows for the recovery of sensible heat from the system's process flow, and the steam is fed into generator 24 for steam conversion and power generation. The generated electricity can be used in the system's electrical equipment, achieving cascaded energy utilization and significantly improving system energy efficiency.

[0025] As a further preferred embodiment of the present invention, the separation device I2 and the separation device II10 are cyclone separators.

[0026] In this embodiment, a cyclone separator is used, which can efficiently separate hydrogen, solid carbon, calcium carbide by-product gas and entrained dust, ensuring the purity of raw materials in subsequent processes and collecting high-purity nano-carbon black. Of course, other separation devices with the same function can also be used, which have the same effect in this system.

[0027] As a further preferred embodiment of the present invention, the methanol synthesis tower 3 is provided with a heat exchange unit, and a steam drum is provided at the top of the methanol synthesis tower 3.

[0028] In this embodiment, a heat exchange unit is provided inside the methanol synthesis tower 3, and a steam drum is provided at the top of the methanol synthesis tower 3, which can efficiently remove the heat of reaction and produce steam as a by-product, so that the methanol synthesis tower 3 can maintain a stable temperature and can be applied to steam power generation according to actual needs.

[0029] As a further preferred embodiment of the present invention, the methane cracking reactor 4 is a vertical pressure vessel, the methane cracking reactor 4 is provided with a molten metal coil 29, the calcium carbide synthesis reactor 6 is surrounded by an induction coil 30, and the calcium carbide synthesis reactor 6 is internally provided with a heating section 31 connected to the molten metal circulation pipeline 11.

[0030] In this embodiment, the methane cracking reactor 4 is an endothermic reaction, adopting a structure of a vertical pressure vessel and a molten metal coil 29. It uses high-temperature molten metal as a high-temperature heat transfer medium to provide a stable and controllable high-temperature heat source for the methane cracking reaction. It has the characteristics of reactor safety, reaction efficiency and adaptability to operating conditions. The induction coil 30 uses the principle of electromagnetic induction to achieve high-temperature heating, quickly providing ultra-high reaction temperature to meet the thermal energy requirements of calcium carbide synthesis. The heating section 31 can assist in heating and form a coordinated heating with the induction coil 30.

[0031] As a further preferred embodiment of the present invention, the molten metal circulation pipeline 11 carries high-temperature molten metal, which serves as a heat transfer medium and is made of a high-temperature nickel-based alloy.

[0032] In this embodiment, high-temperature molten metal is used as a heat transfer medium, which has the characteristics of high thermal conductivity, large heat capacity, good fluidity, and stable physical and chemical properties at high temperatures.

[0033] As a further preferred embodiment of the present invention, the carbon black storage tank 7 is lined with refractory material, the interior of the carbon black storage tank 7 is provided with a high-temperature sealed heat-insulating silo, the carbon black storage tank 7 is provided with a nitrogen or argon gas protection interface, and the outlet end of the carbon black storage tank 7 is provided with a metering feeder.

[0034] In this embodiment, the lining is made of refractory material, which gives the carbon black storage tank 7 high-temperature resistance, ensuring the normal use of the carbon black storage tank 7 and reducing heat loss. The high-temperature sealed insulated silo effectively isolates external air and impurities while achieving heat insulation, preventing material contamination. The carbon black storage tank 7 is equipped with a nitrogen or argon gas protection interface, which is explosion-proof and flame-retardant to eliminate the risk of explosion. The metering feeder can accurately deliver the material in a quantitative manner, ensuring process stability.

[0035] As a further preferred embodiment of the present invention, the mixing and molding unit 9 uses a high-temperature twin-shaft paddle mixer for mixing.

[0036] In this embodiment, a high-temperature twin-shaft paddle mixer is used, which has the characteristics of high temperature resistance, meets the requirements of continuous high-temperature operation, achieves efficient and uniform mixing, and ensures the uniformity of materials.

[0037] Further, as a preferred embodiment of the present invention, the particle size of the calcium oxide feed pipe 17 is 50~500μm, and the temperature of the by-product gas of the calcium carbide synthesis reactor 6 is 1800~1900℃. This gas is used as a heat source to enter the calcium oxide preheating furnace 8 for heat exchange, and the raw material of the calcium oxide feed pipe 17 is preheated to 900℃.

[0038] In this embodiment, the process effectively utilizes waste heat, achieving heat energy recovery and utilization, and also improving the efficiency of subsequent reactions.

[0039] As a further preferred embodiment of the present invention, the generator 24 is a steam turbine generator set, which includes a steam turbine and a condensing system.

[0040] In this embodiment, the high-pressure superheated steam generated by the system enters the steam turbine and flows at high speed, impacting the turbine blades and driving the rotor to rotate at high speed. This efficiently converts the internal energy and pressure energy of the steam into continuous and stable rotational mechanical energy. The generator 24 converts the mechanical energy into industrial frequency alternating current to generate electricity. The condensing system can establish a steam turbine exhaust vacuum, improve work efficiency, and recover condensate to achieve a closed-loop working fluid circulation, remove waste heat from the system, and maintain the system's thermal balance.

[0041] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0042] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A molten media heat storage integrated system for methane cracking, calcium carbide synthesis and methanol production, characterized in that: It includes a methane feedstock gas unit, a methane cracking unit, a separation unit I, a calcium carbide synthesis unit, a gas purification unit, a methanol synthesis tower, and an energy recovery and power generation unit; The methane cracking unit includes a methane cracking reactor and a heat exchanger I. The methane feed gas unit input is transported to the methane cracking reactor after passing through the heat exchanger I. The calcium carbide synthesis unit includes a calcium carbide synthesis reactor, a carbon black storage tank, a calcium oxide preheating furnace, a mixing and forming unit, and a separation device II. A molten metal circulation pipeline is provided between the methane cracking reactor and the calcium carbide synthesis reactor, and a high-temperature pump is provided on the molten metal circulation pipeline. The output of the methane cracking reactor is connected to separation device I. The output of separation device I is connected to heat exchanger II. Cooling water pipeline I is installed at the input of heat exchanger II. The output of heat exchanger II is connected to heat exchanger I. The output of heat exchanger I is connected to heat exchanger III. Cooling water pipeline II is installed at the input of heat exchanger III. The material discharged from the methane cracking reactor is separated by separation device I, and the resulting solid nano-carbon black is transported to a carbon black storage tank. The carbon black storage tank and the calcium oxide preheating furnace are respectively connected to the mixing and forming unit. The calcium oxide preheating furnace is equipped with a calcium oxide feed pipeline. The mixing and forming unit fully mixes the preheated calcium oxide and the nano-carbon black output from the carbon black storage tank. The mixed material output from the mixing and forming unit enters the calcium carbide synthesis reactor. The calcium carbide synthesis reactor outputs high-temperature crude calcium carbide synthesis by-product gas to the calcium oxide preheating furnace for heating. The output of the calcium carbide synthesis reactor is connected to heat exchanger IV. The input of heat exchanger IV is equipped with cooling water pipeline III. The output of heat exchanger IV is equipped with CaC2 pipeline. The crude calcium carbide synthesis by-product gas output from the calcium oxide preheating furnace after heat exchange with calcium oxide is sent to separation device II. The output of separation device II is connected to heat exchanger V. The output of heat exchanger V is connected to heat exchanger VI. The input of heat exchanger V is equipped with cooling water pipeline IV. Heat exchanger VI is connected to the output of the gas purification unit. The high-temperature crude calcium carbide synthesis by-product gas exchanges heat with calcium oxide and then exchanges heat with the cooling water in cooling water pipeline IV. The energy recovery power generation unit includes a generator, and heat exchangers II, III, IV and V are respectively connected to the generator for output. The output of heat exchanger III is connected to heat exchanger VII. The gas purification unit includes a gas separation device. The H2 produced by the gas separation device is sent to the methanol synthesis tower after passing through heat exchanger VII. The output of the methanol synthesis tower is connected to a crude methanol storage tank. The output of the gas separation device is connected to a CO storage tank. The high-temperature crude calcium carbide synthesis by-product gas is heat exchanged with the cooling water in cooling water pipeline IV in heat exchanger V after passing through calcium oxide heat exchanger. Then, it is heat exchanged with the CO output from the CO storage tank through heat exchanger VI. The output of heat exchanger VI is connected to the methanol synthesis tower. The CH4 output from the gas separation device is returned to the methane feed gas unit.

2. The integrated system for the production of methane cracking, calcium carbide synthesis and methanol by using molten medium heat storage according to claim 1, characterized in that: The separation device I and separation device II are cyclone separators.

3. The integrated system for the production of methane cracking, calcium carbide synthesis and methanol by using molten medium heat storage according to claim 1, characterized in that: The methanol synthesis tower is equipped with a heat exchange unit, and a steam drum is installed at the top of the methanol synthesis tower.

4. The integrated system for the production of methane, calcium carbide and methanol by the decomposition of methane in a molten medium according to claim 1, characterized in that: The methane cracking reactor is a vertical pressure vessel, and the methane cracking reactor is equipped with a molten metal coil. The calcium carbide synthesis reactor is surrounded by an induction coil, and the interior of the calcium carbide synthesis reactor is embedded with a heating section connected to the molten metal circulation pipeline.

5. The integrated system for molten medium thermal storage methane cracking, calcium carbide synthesis, and methanol preparation according to claim 1, characterized in that: The molten metal circulation pipeline carries high-temperature molten metal, which serves as a heat transfer medium and is made of a high-temperature nickel-based alloy.

6. The integrated system for molten medium thermal storage methane cracking, calcium carbide synthesis, and methanol preparation according to claim 1, characterized in that: The carbon black storage tank is lined with refractory material, and has a high-temperature sealed insulated silo inside. The carbon black storage tank is equipped with a nitrogen or argon gas protection port, and a metering feeder is installed at the outlet end of the carbon black storage tank.

7. The integrated system for molten medium thermal storage methane cracking, calcium carbide synthesis, and methanol preparation according to claim 1, characterized in that: The mixing and molding unit uses a high-temperature twin-shaft paddle mixer for mixing.

8. The integrated system for molten medium thermal storage methane cracking, calcium carbide synthesis, and methanol preparation according to claim 1, characterized in that: The particle size of the calcium oxide feed pipeline is 50~500μm, and the temperature of the by-product gas of the calcium carbide synthesis reactor is 1800~1900℃. It is used as a heat source to enter the calcium oxide preheating furnace for heat exchange, and the raw material of the calcium oxide feed pipeline is preheated to 900℃.

9. The integrated system for molten medium thermal storage methane cracking, calcium carbide synthesis, and methanol preparation according to claim 1, characterized in that: The generator is a steam turbine generator set, which includes a steam turbine and a condensing system.

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